Data: MediumMedium quality — at least 60% of universal parameters and pins are present, but some key data is missing. Verify specific values against datasheets before critical use.
Low-power DHT triode with UX4 base but 2V filament (battery operation); similar mu (~8) and low-current design
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)135V
Typical Operating
Anode Voltage (typical)Anode Voltage (typical)135V
Grid 1 Bias VoltageGrid Bias Voltage-9V
Anode CurrentAnode Current3mA
Notes
The 01A (Type 201-A) is a directly heated triode with a 5V/0.25A thoriated tungsten filament. Designed by RCA, it became the standard general-purpose amplifier and detector tube of the 1920s-30s radio era.
Class A amplifier at Va=90V: Vg=-4.5V, Ia=2.5mA, mu=8, gm=0.725 mA/V, ra=11000 Ohm.
Class A amplifier at Va=135V: Vg=-9V, Ia=3mA, mu=8, gm=0.8 mA/V, ra=10000 Ohm.
Grid-leak detector operation: Va=45V with Rg=0.25-5.0 Mohm. Biased detector at Va=90-135V biased to 0.2mA anode current.
No explicit Pa_max is given on the RCA datasheet; the maximum rated plate voltage is 135V for Class A amplifier service.
Pin Layout — UX4
1Filament
2Anode
3Grid
4Filament
Socket-Compatible Tubes ⚠ Not electrically compatible